Location of Stolane site, in Radfjorden, Alver municipality, Vestland county, Norway, where rainbow trout escaped.
Image: Screenshot from Barentswatch.
On May 31, Lerøy Vest Sjø AS informed the Norwegian Food Safety Authority (Mattilsynet) about an escape incident at the Stolane site in Radfjorden, in the municipality of Alver, Vestland county, Norway. This time it involved a rainbow trout farming facility.
According to information provided by Mattilsynet, the incident occurred in connection with a groove change, investigations showed two larger holes in it. The Directorate of Fisheries has initiated monitoring of the incident.
Neither the company nor the authority has yet reported on the final number of escaped rainbow trout, which remains undetermined. As of June 2, Lerøy had caught about 126 rainbow trout in its own recapture fishery at the plant.
The bad news keeps coming for Lerøy Seafood. Earlier this week we learned that on May 28 it reported to Mattilsynet a suspected outbreak of infectious salmon anemia (ISA) at another site also operated by its subsidiary Lerøy Vest Sjø AS. Previously, local Norwegian media Børsen Dagbladet had revealed its Reitholmen facility, Hitra, which had reported an escape incident in early May, was affected by bacterial kidney disease (BKD).
As reported by WeAreAquaculture, there was already suspicion in early May that escaped salmon from a Lerøy Midt facility in Reitholmen, Hitra, could be carrying serious diseases. The company initially reported that 14,000 fish ready for harvest had escaped, but this estimate was later reduced to 8,400, while recapture efforts were ongoing.
Some days later, the Norwegian Directorate of Fisheries ordered an extension of the at-sea recapture fishing. At that time some 1,200 farmed salmon had already been recaptured. The Børsen Dagbladet confirmed that, as feared, the Lerøy facility in Reitholmen was infected with BKD.
Now, the Norwegian newspaper also reveals that 12 of 15 facilities where BKD infection has been detected in central Norway since January last year belong to the Lerøy Group. Sources at the Food Safety Authority Region Midt told Børsen that the first two facilities where BKD was detected were Lerøy's sites Ringholmen and Gunnarøya, which are close to each other, and just three kilometers as the crow flies to Reitholmen, where the escape occurred.
Twelve of the fifteen sites affected by BKD are in Trøndelag, while the last three are in Møre and Romsdal. As the infection has spread, Mattilsynet has been imposing strict measures to control it, ordering tight restrictions on the use of containers and equipment between infected facilities. However, the source of the infection remains unknown.
However, according to Børsen's information, the Norwegian Food Safety Authority believes it is highly likely that the spread occurred "via the movement of equipment or vessels between the facilities at Lerøy." Although, they say, they also cannot rule out spread between installations in the sea.
From Mattilsynet they also point to a common denominator in most of the installations where infection has been detected: they released fish before the infection was discovered in the first installations at Ringholmen and Gunnarøya. It must be assumed, they told Børsen, that the infection at the first facilities had been there for some time before it was detected.
For his part, Lerøy Midt CEO Harald Larssen told the Norwegian newspaper that the company no longer has cages where there are fish known to be infected with BKD, as with sampling and thorough monitoring, Lerøy managed to detect all cases "very early in the development of the disease". He added that the company has intensified washing and disinfection requirements when moving equipment between locations and, together with other stakeholders, has extended monitoring to all locations in central Norway.
Larssen also confirmed that the main source of infection is currently unknown. According to him, wild fish in Norway are considered the most important reservoir of BKD infection and the bacterium grows slowly, so it takes a long time from the time the fish is infected until it develops the disease.
Sources at the Norwegian Food Safety Authority confirmed that it cannot be ruled out that the infection has been hidden in the premises for a long time because BKD develops as the fish grow. That means that most of the infection may have occurred before the first diagnosis.
Finally, information from Børsen Dagbladet, noted that the three remaining sites included in Mattilsynet's BKD list for central Norway belong to Mowi. The salmon giant told the media that it will not "speculate" on the causes of the BKD infection at its facilities or others.
*Source:
– 'Ukjent smittekilde - én fellesnevner', Børsen Dagbladet article by Halldor Hustadnes and Oda Ording.